Reflectarea

Reflectarea refers to the process and result of reflecting, either as a physical phenomenon of waves or as a geometric transformation that creates mirror images.

In optics, reflection occurs when incident light strikes a boundary and changes direction. The law of reflection states that the angle of incidence equals the angle of reflection relative to the normal. Specular reflection from smooth surfaces yields clear images, while diffuse reflection from rough surfaces scatters light in many directions.

Reflectance is quantified by the reflectance coefficient, the fraction of incident light that is reflected, depending on material, surface finish, and wavelength. Highly polished metals and mirrors have high reflectance; matte or textured surfaces reflect less and often with wavelength-dependent behavior. In acoustics, reflection of sound can cause echoes and reverberation.

In geometry, reflection is a transformation that maps every point to its mirror image across a line (2D) or a plane (3D). It preserves distances but reverses orientation, and is a basic isometry used in computer graphics and design.

Applications and limitations: reflectarea informs imaging systems, solar energy design, architectural lighting and acoustics. Real surfaces absorb part of energy and reflect only a portion; microstructure affects scattering and polarization.